Diesel engines have long been recognized for their economic capabilities and are now widely accepted for automotive and other vehicle applications. Part of this acceptance has been achieved by the introduction of fuel heaters in the engine fuel systems to assure proper operation during cold weather conditions.
That is, diesel fuel contains a waxy constituent which precipitates out as small crystals when the fuel temperature drops below its "cloud point". Typically, this cloud point may be about 30.degree. F. for some grades of diesel fuel. During cold weather operation, these wax crystals can gradually plug the fuel filter, cutting off delivery to the engine. Fuel heaters, such as the Master Fuel Heater Model A-10 manufactured by Stanadyne, Inc. can eliminate this fuel flow problem. As an in-line component of the fuel feed system, it is positioned upstream of the filter, and it is operated responsive to fuel temperature automatically to heat the fuel if the temperature thereof approaches or reaches the "cloud point".
It is the general object of the present invention to improve the efficacy of such heater by reducing the load thereon during its periods of operation.